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Experimental data for H2 (Hydrogen diatomic)

22 02 02 11 45
INChI INChIKey SMILES IUPAC name
InChI=1S/H2/h1H/q+1 ZZIJOQHRUPVPQC-UHFFFAOYSA-N [H][H+]
State Conformation
2Σg+ D*H
Enthalpy of formation (Hfg), Entropy, Integrated heat capacity (0 K to 298.15 K) (HH), Heat Capacity (Cp)
Property Value Uncertainty units Reference Comment
Hfg(298.15K) enthalpy of formation 1494.67 0.00 kJ mol-1 webbook
Hfg(0K) enthalpy of formation 1488.36 0.00 kJ mol-1 webbook
Entropy (298.15K) entropy 142.37 0.04 J K-1 mol-1 webbook
Integrated Heat Capacity (0 to 298.15K) integrated heat capacity 8.58   kJ mol-1 webbook
Heat Capacity (298.15K) heat capacity 29.29   J K-1 mol-1 webbook
Information can also be found for this species in the NIST Chemistry Webbook
Vibrational levels (cm-1) vibrations
Mode Number Symmetry Frequency Intensity Comment Description
Fundamental(cm-1) Harmonic(cm-1) Reference (km mol-1) unc. Reference
1 Σ 2191 2322 webbook      

Detailed diatomic data
ωe ωexe ωeye Be αe ZPE reference
2321.7 66.2 0.6 30.21 1.685 1150.024 2007Iri:389

vibrational zero-point energy: 1095.6 cm-1 (from fundamental vibrations)
Calculated vibrational frequencies for H2 (Hydrogen diatomic).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment

Calculated rotational constants for H2 (Hydrogen diatomic).
Product of moments of inertia moments of inertia
amu3Å6   0gm3 cm6
Geometric Data
picture of Hydrogen diatomic

Point Group D∞h


Internal coordinates
distances (r) in Å, angles (a) in degrees, dihedrals (d) in degrees
Description Value unc. Connectivity Reference Comment
Atom 1 Atom 2 Atom 3 Atom 4

Cartesians
Atom x (Å) y (Å) z (Å)

Atom - Atom Distances bond lengths
Distances in Å
 

Calculated geometries for H2 (Hydrogen diatomic).

Bond descriptions


Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond
Bond Type Count
H-H 1

Connectivity
Atom 1 Atom 2
H1 H2
Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 2   2Σg+
Dipole, Quadrupole and Polarizability
Electric dipole moment dipole
State Config State description Conf description Exp. min. Dipole (Debye) Reference comment Point Group Components
x y z total dipole quadrupole
1 1 2Σg+ D∞h True           D∞h 0 1
Experimental dipole measurement abbreviations: MW microwave; DT Dielectric with Temperature variation; DR Indirect (usually an upper limit); MB Molecular beam
Calculated electric dipole moments for H2 (Hydrogen diatomic).
Electric quadrupole moment quadrupole
State Config State description Conf description Exp. min. Quadrupole (D Å) Reference comment Point Group Components
xx yy zz dipole quadrupole
1 1 2Σg+ D∞h True       D∞h 0 1

Calculated electric quadrupole moments for H2 (Hydrogen diatomic).
Electric dipole polarizability (Å3) polarizability
alpha unc. Reference
0.469 0.000 2000Jac/Kom:012509

Calculated electric dipole polarizability for H2 (Hydrogen diatomic).

References
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squib reference DOI
2000Jac/Kom:012509 PL Jacobsen, RA Komara, WG Sturrus, SR Lundeen "Microwave spectroscopy of heliumlike Rydberg states of H2 and D2: Determination of the dipole polarizabilities of H2+ and D2+ ground states" Physical Review A 62, 012509 (2000) 10.1103/PhysRevA.62.012509
2007Iri:389 KK Irikura "Experimental Vibrational Zero-Point Energies: Diatomic Molecules" J. Phys. Chem. Ref. Data 36(2), 389, 2007 10.1063/1.2436891
webbook NIST Chemistry Webbook (http://webbook.nist.gov/chemistry) 10.18434/T4D303

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